Ophthalmologists employ both contact and noncontact indirect ophthalmoscopy lenses for viewing the fundus of the eye. These lenses, which provide an aerial image of the fundus anterior to the lens, are used for both diagnosis and for subsequent laser treatment where indicated. Typically, an ophthalmologist prefers to first use a low magnification wide field lens in order to obtain an overview of the patient's fundus. The ophthalmologist then switches to a higher magnification lens in order to examine a specific area of interest in greater detail. Switching of lenses is time-consuming and cumbersome, especially in the case of contact lenses. Also, physicians with heavy patient schedules and multiple examination rooms encounter difficulty in tracking the whereabouts of various lenses of different power.
Rather than switching lenses to magnify the image of the fundus, the variable magnification capabilities of the slit lamp or indirect ophthalmoscope are used by the physician to magnify the fundus image. While this provides greater magnification for the ophthalmologist, it provides little or no increase in the amount of information or fundus detail available to the physician.